PDFBOX-6180: improve directory boundary check, as suggested by Kaixuan Li; closes #427

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1932444 13f79535-47bb-0310-9956-ffa450edef68

Author: THausherr

examples/src/main/java/org/apache/pdfbox/examples/pdmodel/ExtractEmbeddedFiles.java

@@ -141,7 +141,9 @@ private static void extractFile(String filename, PDEmbeddedFile embeddedFile, St
     {
         File file = new File(directoryPath, filename);
         File parentDir = file.getParentFile();
-        if (!parentDir.getCanonicalPath().startsWith(directoryPath))
+        String parentCanonical = parentDir.getCanonicalPath();
+        if (!parentCanonical.equals(directoryPath) &&
+            !parentCanonical.startsWith(directoryPath + File.separator))
         {
             System.err.println("Ignoring " + filename + " (different directory)");
             return;